Quentin Malé, Sergey Shcherbanev, Matteo Impagnatiello, Nicolas Noiray
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引用次数: 0
Abstract
Plasma-assisted combustion using Nanosecond Repetitively Pulsed Discharges (NRPDs) is an emerging technology that enhances the reactivity of fuel–air mixtures, offering significant improvements in operational and fuel flexibility—two crucial features for future sustainable gas turbines. The mechanisms that enable the stabilization of thermoacoustically unstable burners, however, remain unclear. Thus, to investigate the physical phenomena involved, we performed a massively parallel Large Eddy Simulation (LES) of the stabilization of a thermoacoustically unstable sequential combustor by NRPDs at atmospheric pressure. LES is combined with an accurate description of the combustion chemistry and a state-of-the-art phenomenological model for the non-equilibrium plasma effects. In this work, we have validated the simulation framework by comparison with experimental data including acoustic pressure and Heat Release Rate (HRR) signals in both stages of the sequential combustor, and OH-planar laser-induced fluorescence images in the second stage combustion chamber. Hence, this study provides a robust LES framework to study the effects of NRPDs on Thermoacoustic Instabilities (TIs). In addition, the analysis of the LES data reveals a significant decrease of the acoustic energy production in the sequential combustor thanks to the NRPDs. Surprisingly, the steady NRPD actuation generates HRR fluctuations upstream of the combustion chamber, which are in phase opposition to the acoustic pressure, inducing locally a sink term in the acoustic energy balance equation. Moreover, an analysis of the acoustic energy production during the onset of the TI reveals the predominant role of the second stage in developing and sustaining the self-excited TI. The effect of plasma is therefore very effective in stabilizing the system by reducing the acoustic energy production in the sequential stage.
期刊介绍:
The Proceedings of the Combustion Institute contains forefront contributions in fundamentals and applications of combustion science. For more than 50 years, the Combustion Institute has served as the peak international society for dissemination of scientific and technical research in the combustion field. In addition to author submissions, the Proceedings of the Combustion Institute includes the Institute''s prestigious invited strategic and topical reviews that represent indispensable resources for emergent research in the field. All papers are subjected to rigorous peer review.
Research papers and invited topical reviews; Reaction Kinetics; Soot, PAH, and other large molecules; Diagnostics; Laminar Flames; Turbulent Flames; Heterogeneous Combustion; Spray and Droplet Combustion; Detonations, Explosions & Supersonic Combustion; Fire Research; Stationary Combustion Systems; IC Engine and Gas Turbine Combustion; New Technology Concepts
The electronic version of Proceedings of the Combustion Institute contains supplemental material such as reaction mechanisms, illustrating movies, and other data.